1. Field of the Invention
This invention relates to an apparatus for drawing out the leading end portion of a web from a web roll, and more particularly to an apparatus for securely drawing out the leading end portion of a paper web from a web roll.
2. Description of the Related Art
In the conventional cigarette manufacturing process, belt-like paper sheets are wound around cigarette material to form elongated cigarette rods, and thereafter the rods are cut into pieces each having a predetermined length. Similarly, when filters are manufactured in the conventional process, belt-like paper sheets are also wound around filter sheets made of fiber or the like to form elongated filter rods and thereafter the filter rods are cut into pieces each having a predetermined length.
Therefore, continuous supply of the above-mentioned belt-like paper pieces, i.e., webs is required for producing cigarette rods and filter rods. Such a web is usually supplied in a form of a web roll comprising a core and a web wound around a roll, as shown in FIG. 7. The web roll is mounted in a web supplying apparatus and the web is continuously taken off from the web roll and is supplied therefrom to the succeeding apparatus. When the web on the web roll is fully used, a web is taken off from a new web roll and the leading end of the new web is connected to the trailing end of the web from the old web roll. In such a way, webs are supplied continuously.
There has been recently developed a web supplying device which is provided with two web rolls so as to perform these processes automatically. A web is taken off from a first web roll and is supplied to the succeeding apparatus. When the web on the first web roll is fully used, a web is drawn out from the second web roll which was in a waiting state, and the leading end of the web on the second web roll is automatically connected to the trailing end of the web of the first web rib. Thereafter, the core and other necessary parts are removed from the web supplying apparatus, and a new web roll is mounted thereon. With this web supplying device, this series of web supplying and web replacing processes is repeated so that webs are supplied continuously.
With this conventional apparatus, it is necessary to securely draw out the leading end portion of the web from the new web roll. In the general web roll, the leading end portion of the web is temporarily attached to the body of the web by an adhesive tape or the like which has a weak adhering force and a part of the web between the adhesive tape and the front edge of the leading end portion is left as a detaching part. After the detaching part has been held by a chuck or the like, the leading end portion of the web is drawn out.
When the detaching part is too long, however, it is likely to be caught by an apparatus part and the leading end portion of the web is likely to be separated from the body of the web. Further, a too long detaching part is easily bent or folded, making it difficult to be held by the chuck or the like. In this connection, the detaching part cannot be made too long. In most cases, the detaching parts closely contacts the webs. Therefore, an apparatus for securely holding and drawing out the leading end portion of the web has been demanded.
A conventional apparatus for drawing out the leading end portion of a web is provided with a chuck having a sharp forward end. The web roll is rotated in a state in which the forward end of the chuck is slightly contacted with the peripheral surface of the web on the web roll. The detaching part of the web is separated from the body of the web, and then is held by the chuck. With this conventional apparatus, however, the outer surface of the web on the web roll is likely to be caught by the sharp edges of the forward portion of the chuck, resulting in web damage.